1. Field of the Invention
The invention relates to an ebullated bed process for converting a residual hydrocarbon oil to a product oil comprising an increased amount of sediment. More particularly, the invention relates to selecting a hydrogen partial pressure to achieve a selected amount of sediment.
2. Description of Other Related Methods in the Field
The ebullated bed process comprises the passing of concurrently flowing streams of liquids, or slurries of liquids and solids, and gas through a vertically elongated fluidized catalyst bed. The catalyst is fluidized and completely mixed by the upwardly flowing liquid streams. The ebullated bed process has found commercial application in the upgrading of heavy liquid hydrocarbons and converting coal to synthetic oils.
The process is generally described in U.S. Pat. No. 25,770 to Johanson incorporated herein by reference. A mixture of hydrocarbon liquid and hydrogen is passed upwardly through a bed of catalyst particles at a rate such that the particles are forced into random motion as the liquid and gas pass upwardly through the bed. The catalyst bed motion is controlled by a recycle liquid flow so that at steady state, the bulk of the catalyst does not rise above a definable level in the reactor. Vapors along with the liquid which is being hydrogenated pass through that upper level of catalyst particles into a substantially catalyst free zone and are removed from the upper portion of the reactor.
U.S. Pat. No. 5,156,733 to G. Nongbri et al. discloses a method of controlling sediment in an ebullated bed process. In switching from one sediment yielding feedstock to another, transient carbon release from the catalyst is controlled.
U.S. Pat. No. 4,427,535 to G. Nongbri et al. discloses an ebullated bed process for the hydroconversion of special petroleum feedstocks. Reactor temperature and hydrogen partial pressure are shown to be related to the conversion of 975.degree. F..sup.+ feedstock.
U.S. Pat. No. 3,553,105 to E. T. Layng et al. discloses an ebullated bed process for removing sulfur from a liquid hydrocarbon feedstock. Process operating conditions including feedstock characterization, temperature, pressure, catalyst age and activity are adjusted to achieve desulfurization.